1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Copyright (C) 2019 Laurent Pinchart <laurent.pinchart@ideasonboard.com> 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/module.h> 8 #include <linux/slab.h> 9 10 #include <drm/drm_atomic_state_helper.h> 11 #include <drm/drm_bridge.h> 12 #include <drm/drm_bridge_connector.h> 13 #include <drm/drm_connector.h> 14 #include <drm/drm_device.h> 15 #include <drm/drm_edid.h> 16 #include <drm/drm_modeset_helper_vtables.h> 17 #include <drm/drm_probe_helper.h> 18 19 /** 20 * DOC: overview 21 * 22 * The DRM bridge connector helper object provides a DRM connector 23 * implementation that wraps a chain of &struct drm_bridge. The connector 24 * operations are fully implemented based on the operations of the bridges in 25 * the chain, and don't require any intervention from the display controller 26 * driver at runtime. 27 * 28 * To use the helper, display controller drivers create a bridge connector with 29 * a call to drm_bridge_connector_init(). This associates the newly created 30 * connector with the chain of bridges passed to the function and registers it 31 * with the DRM device. At that point the connector becomes fully usable, no 32 * further operation is needed. 33 * 34 * The DRM bridge connector operations are implemented based on the operations 35 * provided by the bridges in the chain. Each connector operation is delegated 36 * to the bridge closest to the connector (at the end of the chain) that 37 * provides the relevant functionality. 38 * 39 * To make use of this helper, all bridges in the chain shall report bridge 40 * operation flags (&drm_bridge->ops) and bridge output type 41 * (&drm_bridge->type), as well as the DRM_BRIDGE_ATTACH_NO_CONNECTOR attach 42 * flag (none of the bridges shall create a DRM connector directly). 43 */ 44 45 /** 46 * struct drm_bridge_connector - A connector backed by a chain of bridges 47 */ 48 struct drm_bridge_connector { 49 /** 50 * @base: The base DRM connector 51 */ 52 struct drm_connector base; 53 /** 54 * @encoder: 55 * 56 * The encoder at the start of the bridges chain. 57 */ 58 struct drm_encoder *encoder; 59 /** 60 * @bridge_edid: 61 * 62 * The last bridge in the chain (closest to the connector) that provides 63 * EDID read support, if any (see &DRM_BRIDGE_OP_EDID). 64 */ 65 struct drm_bridge *bridge_edid; 66 /** 67 * @bridge_hpd: 68 * 69 * The last bridge in the chain (closest to the connector) that provides 70 * hot-plug detection notification, if any (see &DRM_BRIDGE_OP_HPD). 71 */ 72 struct drm_bridge *bridge_hpd; 73 /** 74 * @bridge_detect: 75 * 76 * The last bridge in the chain (closest to the connector) that provides 77 * connector detection, if any (see &DRM_BRIDGE_OP_DETECT). 78 */ 79 struct drm_bridge *bridge_detect; 80 /** 81 * @bridge_modes: 82 * 83 * The last bridge in the chain (closest to the connector) that provides 84 * connector modes detection, if any (see &DRM_BRIDGE_OP_MODES). 85 */ 86 struct drm_bridge *bridge_modes; 87 }; 88 89 #define to_drm_bridge_connector(x) \ 90 container_of(x, struct drm_bridge_connector, base) 91 92 /* ----------------------------------------------------------------------------- 93 * Bridge Connector Hot-Plug Handling 94 */ 95 96 static void drm_bridge_connector_hpd_notify(struct drm_connector *connector, 97 enum drm_connector_status status) 98 { 99 struct drm_bridge_connector *bridge_connector = 100 to_drm_bridge_connector(connector); 101 struct drm_bridge *bridge; 102 103 /* Notify all bridges in the pipeline of hotplug events. */ 104 drm_for_each_bridge_in_chain(bridge_connector->encoder, bridge) { 105 if (bridge->funcs->hpd_notify) 106 bridge->funcs->hpd_notify(bridge, status); 107 } 108 } 109 110 static void drm_bridge_connector_hpd_cb(void *cb_data, 111 enum drm_connector_status status) 112 { 113 struct drm_bridge_connector *drm_bridge_connector = cb_data; 114 struct drm_connector *connector = &drm_bridge_connector->base; 115 struct drm_device *dev = connector->dev; 116 enum drm_connector_status old_status; 117 118 mutex_lock(&dev->mode_config.mutex); 119 old_status = connector->status; 120 connector->status = status; 121 mutex_unlock(&dev->mode_config.mutex); 122 123 if (old_status == status) 124 return; 125 126 drm_bridge_connector_hpd_notify(connector, status); 127 128 drm_kms_helper_hotplug_event(dev); 129 } 130 131 /** 132 * drm_bridge_connector_enable_hpd - Enable hot-plug detection for the connector 133 * @connector: The DRM bridge connector 134 * 135 * This function enables hot-plug detection for the given bridge connector. 136 * This is typically used by display drivers in their resume handler. 137 */ 138 void drm_bridge_connector_enable_hpd(struct drm_connector *connector) 139 { 140 struct drm_bridge_connector *bridge_connector = 141 to_drm_bridge_connector(connector); 142 struct drm_bridge *hpd = bridge_connector->bridge_hpd; 143 144 if (hpd) 145 drm_bridge_hpd_enable(hpd, drm_bridge_connector_hpd_cb, 146 bridge_connector); 147 } 148 EXPORT_SYMBOL_GPL(drm_bridge_connector_enable_hpd); 149 150 /** 151 * drm_bridge_connector_disable_hpd - Disable hot-plug detection for the 152 * connector 153 * @connector: The DRM bridge connector 154 * 155 * This function disables hot-plug detection for the given bridge connector. 156 * This is typically used by display drivers in their suspend handler. 157 */ 158 void drm_bridge_connector_disable_hpd(struct drm_connector *connector) 159 { 160 struct drm_bridge_connector *bridge_connector = 161 to_drm_bridge_connector(connector); 162 struct drm_bridge *hpd = bridge_connector->bridge_hpd; 163 164 if (hpd) 165 drm_bridge_hpd_disable(hpd); 166 } 167 EXPORT_SYMBOL_GPL(drm_bridge_connector_disable_hpd); 168 169 /* ----------------------------------------------------------------------------- 170 * Bridge Connector Functions 171 */ 172 173 static enum drm_connector_status 174 drm_bridge_connector_detect(struct drm_connector *connector, bool force) 175 { 176 struct drm_bridge_connector *bridge_connector = 177 to_drm_bridge_connector(connector); 178 struct drm_bridge *detect = bridge_connector->bridge_detect; 179 enum drm_connector_status status; 180 181 if (detect) { 182 status = detect->funcs->detect(detect); 183 184 drm_bridge_connector_hpd_notify(connector, status); 185 } else { 186 switch (connector->connector_type) { 187 case DRM_MODE_CONNECTOR_DPI: 188 case DRM_MODE_CONNECTOR_LVDS: 189 case DRM_MODE_CONNECTOR_DSI: 190 case DRM_MODE_CONNECTOR_eDP: 191 status = connector_status_connected; 192 break; 193 default: 194 status = connector_status_unknown; 195 break; 196 } 197 } 198 199 return status; 200 } 201 202 static void drm_bridge_connector_destroy(struct drm_connector *connector) 203 { 204 struct drm_bridge_connector *bridge_connector = 205 to_drm_bridge_connector(connector); 206 207 if (bridge_connector->bridge_hpd) { 208 struct drm_bridge *hpd = bridge_connector->bridge_hpd; 209 210 drm_bridge_hpd_disable(hpd); 211 } 212 213 drm_connector_unregister(connector); 214 drm_connector_cleanup(connector); 215 216 kfree(bridge_connector); 217 } 218 219 static const struct drm_connector_funcs drm_bridge_connector_funcs = { 220 .reset = drm_atomic_helper_connector_reset, 221 .detect = drm_bridge_connector_detect, 222 .fill_modes = drm_helper_probe_single_connector_modes, 223 .destroy = drm_bridge_connector_destroy, 224 .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, 225 .atomic_destroy_state = drm_atomic_helper_connector_destroy_state, 226 }; 227 228 /* ----------------------------------------------------------------------------- 229 * Bridge Connector Helper Functions 230 */ 231 232 static int drm_bridge_connector_get_modes_edid(struct drm_connector *connector, 233 struct drm_bridge *bridge) 234 { 235 enum drm_connector_status status; 236 struct edid *edid; 237 int n; 238 239 status = drm_bridge_connector_detect(connector, false); 240 if (status != connector_status_connected) 241 goto no_edid; 242 243 edid = bridge->funcs->get_edid(bridge, connector); 244 if (!drm_edid_is_valid(edid)) { 245 kfree(edid); 246 goto no_edid; 247 } 248 249 drm_connector_update_edid_property(connector, edid); 250 n = drm_add_edid_modes(connector, edid); 251 252 kfree(edid); 253 return n; 254 255 no_edid: 256 drm_connector_update_edid_property(connector, NULL); 257 return 0; 258 } 259 260 static int drm_bridge_connector_get_modes(struct drm_connector *connector) 261 { 262 struct drm_bridge_connector *bridge_connector = 263 to_drm_bridge_connector(connector); 264 struct drm_bridge *bridge; 265 266 /* 267 * If display exposes EDID, then we parse that in the normal way to 268 * build table of supported modes. 269 */ 270 bridge = bridge_connector->bridge_edid; 271 if (bridge) 272 return drm_bridge_connector_get_modes_edid(connector, bridge); 273 274 /* 275 * Otherwise if the display pipeline reports modes (e.g. with a fixed 276 * resolution panel or an analog TV output), query it. 277 */ 278 bridge = bridge_connector->bridge_modes; 279 if (bridge) 280 return bridge->funcs->get_modes(bridge, connector); 281 282 /* 283 * We can't retrieve modes, which can happen for instance for a DVI or 284 * VGA output with the DDC bus unconnected. The KMS core will add the 285 * default modes. 286 */ 287 return 0; 288 } 289 290 static const struct drm_connector_helper_funcs drm_bridge_connector_helper_funcs = { 291 .get_modes = drm_bridge_connector_get_modes, 292 /* No need for .mode_valid(), the bridges are checked by the core. */ 293 }; 294 295 /* ----------------------------------------------------------------------------- 296 * Bridge Connector Initialisation 297 */ 298 299 /** 300 * drm_bridge_connector_init - Initialise a connector for a chain of bridges 301 * @drm: the DRM device 302 * @encoder: the encoder where the bridge chain starts 303 * 304 * Allocate, initialise and register a &drm_bridge_connector with the @drm 305 * device. The connector is associated with a chain of bridges that starts at 306 * the @encoder. All bridges in the chain shall report bridge operation flags 307 * (&drm_bridge->ops) and bridge output type (&drm_bridge->type), and none of 308 * them may create a DRM connector directly. 309 * 310 * Returns a pointer to the new connector on success, or a negative error 311 * pointer otherwise. 312 */ 313 struct drm_connector *drm_bridge_connector_init(struct drm_device *drm, 314 struct drm_encoder *encoder) 315 { 316 struct drm_bridge_connector *bridge_connector; 317 struct drm_connector *connector; 318 struct i2c_adapter *ddc = NULL; 319 struct drm_bridge *bridge; 320 int connector_type; 321 322 bridge_connector = kzalloc(sizeof(*bridge_connector), GFP_KERNEL); 323 if (!bridge_connector) 324 return ERR_PTR(-ENOMEM); 325 326 bridge_connector->encoder = encoder; 327 328 /* 329 * TODO: Handle doublescan_allowed, stereo_allowed and 330 * ycbcr_420_allowed. 331 */ 332 connector = &bridge_connector->base; 333 connector->interlace_allowed = true; 334 335 /* 336 * Initialise connector status handling. First locate the furthest 337 * bridges in the pipeline that support HPD and output detection. Then 338 * initialise the connector polling mode, using HPD if available and 339 * falling back to polling if supported. If neither HPD nor output 340 * detection are available, we don't support hotplug detection at all. 341 */ 342 connector_type = DRM_MODE_CONNECTOR_Unknown; 343 drm_for_each_bridge_in_chain(encoder, bridge) { 344 if (!bridge->interlace_allowed) 345 connector->interlace_allowed = false; 346 347 if (bridge->ops & DRM_BRIDGE_OP_EDID) 348 bridge_connector->bridge_edid = bridge; 349 if (bridge->ops & DRM_BRIDGE_OP_HPD) 350 bridge_connector->bridge_hpd = bridge; 351 if (bridge->ops & DRM_BRIDGE_OP_DETECT) 352 bridge_connector->bridge_detect = bridge; 353 if (bridge->ops & DRM_BRIDGE_OP_MODES) 354 bridge_connector->bridge_modes = bridge; 355 356 if (!drm_bridge_get_next_bridge(bridge)) 357 connector_type = bridge->type; 358 359 if (bridge->ddc) 360 ddc = bridge->ddc; 361 } 362 363 if (connector_type == DRM_MODE_CONNECTOR_Unknown) { 364 kfree(bridge_connector); 365 return ERR_PTR(-EINVAL); 366 } 367 368 drm_connector_init_with_ddc(drm, connector, &drm_bridge_connector_funcs, 369 connector_type, ddc); 370 drm_connector_helper_add(connector, &drm_bridge_connector_helper_funcs); 371 372 if (bridge_connector->bridge_hpd) 373 connector->polled = DRM_CONNECTOR_POLL_HPD; 374 else if (bridge_connector->bridge_detect) 375 connector->polled = DRM_CONNECTOR_POLL_CONNECT 376 | DRM_CONNECTOR_POLL_DISCONNECT; 377 378 return connector; 379 } 380 EXPORT_SYMBOL_GPL(drm_bridge_connector_init); 381